Method of producing malt alcohol beverages

ABSTRACT

The method of producing a malt alcohol beverage according to this invention is characterized in that in the production of the malt alcohol beverage an adsorbent is used to remove through adsorption at least a part of rough flavor components from malt, a malt alcohol beverage intermediate product, or the malt alcohol beverage. Such method of producing a malt alcohol beverage enables to provide a method of producing a malt alcohol beverage such that the aging of flavor after production can be suppressed and the flavor immediately after production can be maintained over a prolonged period of time.

TECHNICAL FIELD

This invention relates to a method of producing a malt alcohol beverage. More particularly, it relates to a method of producing a malt alcohol beverage by suppressing the generation of stale flavor after production of the malt alcohol beverage.

BACKGROUND ART

In malt alcohol beverages (such as beer and low-malt beer (Happoshu)) that use malt as a raw material, a variety of reactions, including oxidation and dehydration of their components, are promoted during or after their production by virtue of the lapse of time or the increase in temperature (generally referred to as “the stale flavor of malt alcohol beverages”). Consequently, it is known that the original flavor of malt alcohol beverages is impaired.

Therefore, different measures are taken in order to prevent the qualities of such malt alcohol beverages from being deteriorated. Specifically, among others the quality control after production, the time management after production to sale, the temperature control during transportation are strictly enforced, which allows products with freshness and high quality to be provided. However, even if the aforementioned management is thoroughly employed, it has been difficult to stably maintain the freshness obtained immediately after production for a prolonged period of time.

A method of suppressing the oxidation of a malt alcohol beverage during its production to stably maintain the freshness immediately after production was developed that relays on decreasing the oxygen concentration of the atmosphere in the entire process or a part thereof during the production of the malt alcohol beverage (Japanese Patent Application Laid-Open Gazette No.2000-4866). According to this method, by decreasing the oxygen concentration of the atmosphere during production, the reducing power of intermediate products in the production process is enhanced with the result of increased reducing power of the final product, which has made it possible to enhance resistance to the oxidation-or aging of the malt alcohol beverage.

However, while the method of producing a malt alcohol beverage described in Japanese Patent Application Laid-Open Gazette No.2000-4866 can prevent the malt alcohol beverage from being oxidized to certain degree, it is not necessarily adequate to suppress the aging of the flavor after production for a prolonged period of time.

DISCLOSURE OF THE INVENTION

In light of the aforementioned problems inherent in the prior art this invention has been made, and it aims at providing a method of producing a malt alcohol beverage by which the aging of the flavor after production is suppressed and the flavor immediately after the production can be maintained over a prolonged period of time.

In order to accomplish the aforementioned object, the present inventors researched diligently and consequently, discovered that by removing through adsorption rough flavor (powdery) components in the malt alcohol beverage with the aid of an adsorbent during the production process of the malt alcohol beverage, it was possible to suppress the aging of the flavor after production and to maintain the flavor immediately after the production over a prolonged period of time, thus leading to the completion of this invention.

Specifically, this invention relates to a method of producing a malt alcohol beverage comprising removing through adsorption at least a part of rough flavor components from malt, a malt alcohol beverage intermediate product, or the malt alcohol beverage with the aid of an adsorbent.

Also, in the method of producing a malt alcohol beverage according to this invention, the adsorbent is preferably an ion-exchange resin or a synthetic adsorbent.

Further, in the method of producing a malt alcohol beverage according to the invention, the rough flavor component is a causative substance for the aging of flavor or a precursor thereof: there are mentioned, for example, a carbonyl compound or a Maillard compound.

Also, in the method of producing a malt alcohol beverage according to the invention, the rough flavor component includes an organic acid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph showing the relationship between time and pH upon addition of ion-exchange resins to a low-malt beer.

FIG. 1B is a graph showing the relationship between time and pH upon addition of ion-exchange resins to the low-malt beer.

FIG. 2A is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to the low-malt beer.

FIG. 2B is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to the low-malt beer.

FIG. 3A is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to a beer.

FIG. 3B is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to the beer.

FIG. 4A is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to the beer.

FIG. 4B is a graph showing the relationship between time and pH upon addition of the ion-exchange resins to the beer.

FIG. 5A is a graph showing the sum of hydrophilic peaks as detected by HPLC when ion-exchange resins were added to the low-malt beer.

FIG. 5B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the low-malt beer.

FIG. 6A is a graph showing the sum of hydrophilic peaks as detected by HPLC when the ion-exchange resins were added to the low-malt beer.

FIG. 6B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the low-malt beer.

FIG. 7A is a graph showing the sum of hydrophilic peaks as detected by HPLC when ion-exchange resins were added to the low-malt beer.

FIG. 7B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the low-malt beer.

FIG. 8A is a graph showing the sum of hydrophilic peaks as detected by HPLC when ion-exchange resins were added to the low-malt beer.

FIG. 8B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the low-malt beer.

FIG. 9A is a graph showing the sum of hydrophilic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 9B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 10A is a graph showing the sum of hydrophilic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 10B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 11A is a graph showing the sum of hydrophilic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 11B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 12A is a graph showing the sum of hydrophilic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 12B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the ion-exchange resins were added to the beer.

FIG. 13A is a graph showing the sum of hydrophilic peaks as detected by HPLC when a variety of synthetic adsorbents were added to the low-malt beer.

FIG. 13B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the variety of synthetic adsorbents were added to the low-malt beer.

FIG. 14A is a graph showing the sum of hydrophilic peaks as detected by HPLC when a variety of synthetic adsorbents were added to the beer.

FIG. 14B is a graph showing the sum of hydrophobic peaks as detected by HPLC when the variety of synthetic adsorbents were added to the beer.

FIG. 15 is a graph showing time-dependent variations in the concentration of iso-α acid in the low-malt beer when ion-exchange resins were added to the low-malt beer.

FIG. 16A is a graph showing the contents of organic acids in the low-malt beer when ion-exchange resins were added to the low-malt beer.

FIG. 16B is a graph showing the contents of organic acids in the low-malt beer when ion-exchange resins were added to the low-malt beer.

FIG. 17A is a graph showing the contents of organic acids in the beer wine when the ion-exchange resins were added to the beer.

FIG. 17B is a graph showing the contents of organic acids in the beer when the ion-exchange resins were added to the beer.

FIG. 18A is a graph showing the contents of polyphenols in the low-malt beer when the ion-exchange resins were added to the low-malt beer.

FIG. 18B is a graph showing the contents of polyphenols in the low-malt beer when the ion-exchange resins were added to the low-malt beer.

FIG. 18C is a graph showing the contents of polyphenols in the low-malt beer when synthetic adsorbents were added to the low-malt beer.

FIG. 19A is a graph showing the content of polyphenols in the low-malt beer when the ion-exchange resins were added to the beer.

FIG. 19B is a graph showing the contents of polyphenols in the low-malt beer when the ion-exchange resins were added to the beer.

FIG. 19C is a graph showing the contents of polyphenols in the low-malt beer when the synthetic adsorbents were added to the beer.

FIG. 20A is a graph showing the sum of hydrophilic peaks from the low-malt beer filtered through an adsorbent, as detected by HPLC.

FIG. 20B is a graph showing the sum of hydrophobic peaks from the low-malt beer filtered through the adsorbent, as detected by HPLC.

FIG. 21A is a graph showing the sum of hydrophilic peaks from the beer filtered through an adsorbent, as detected by HPLC.

FIG. 21B is a graph showing the sum of hydrophobic peaks from the beer filtered through the adsorbent, as detected by HPLC.

BEST MODE FOR CARRYING OUT THE INVENTION

This invention will be described in detail with respect to preferred embodiments hereunder.

In the method of producing a malt alcohol beverage comprising: a preparation step of mixing a raw material containing malt with water for preparation, saccharifying the malt by warming the resultant mixture, and collecting wort from the saccharified malt; a fermentation step of fermenting the wort by addition of yeast thereto and obtaining a malt alcohol beverage intermediate product; a storage step of storing the malt alcohol beverage intermediate product (finished fermentation solution) obtained from the fermentation step; and a filtration step of filtering the malt alcohol beverage intermediate product (finished storage solution) obtained from the storage step to produce the malt alcohol beverage, the method of producing a malt alcohol beverage according to this invention is characterized in that it removes through adsorption at Least a part of rough flavor components from malt, the malt alcohol beverage intermediate product, or the malt alcohol beverage with the aid of an adsorbent.

The malt alcohol beverage according to this invention may be any alcoholic beverage produced from malt as its raw material since the use ratio of malt employed in the production, whether large or small, is not particularly limited. Specifically, there are mentioned beer and low-malt beer (malt alcohol beverage with a malt use ratio of less than 67%) among others.

The first step of this invention is a preparation step of mixing a raw material containing malt with water for preparation, saccharifying the malt by warning the resultant mixture, and collecting wort from the saccharified malt.

The malt used in the step is preferably malt produced by providing barley with water and air to germinate and removing rootlets therefrom after drying. The malt serves as an enzyme source necessary for the production of wort and at the same time serves as a principle starch source which is a material to be saccharified. The germinated malt that has been smoke-dried is used in the malt production to give the flavor and the dye characteristic of a malt alcohol beverage. In addition, supplementary materials such as hop, cornstarch, corn grits, rice and sugars other than malt may be added as materials.

In the step of producing the wort, wort may be obtaining by mixing commercially available or prepared malt extract with water for preparation and adding the supplementary materials thereto as necessary.

The malt is added to the water for preparation and then mixed. It the supplementary materials are to be added, they may be admixed here concurrently. The water for preparation is not particularly limited, and appropriate water may be employed depending on the malt alcohol beverage to be produced. Saccharification may be carried out basically under known conditions, and for example, it is preferably carried out by warming the mixed malt and water for preparation at 65-75° C. This allows the saccharification by amylase in the malt to progress. The thus-obtained saccharified malt solution is filtered to yield wort.

The second step of this invention is a fermentation step of fermenting the wort by addition of yeast thereto and obtaining a malt alcohol beverage intermediate product.

The yeasts used here may be any yeasts for alcoholic beverages that produce alcohol, carbon dioxide, and the like by metabolizing sugar in the wort obtainable from the saccharification of malt (so-called “causing alcoholic fermentation”). Specifically, there are mentioned Saccharomyces cerevisiae and Saccharomyces uvarum among others.

The wort obtained in the preparation step is cooled and the yeast as described above is added to carry out fermentation. The fermentation conditions are not essentially different from those known in the art; and the fermentation temperature is usually 15° C. or less, preferably from 8 to 11° C. and the fermentation time is preferably from 8 to 10 days.

The third step of this invention is a storage step of storing the malt alcohol beverage intermediate product obtained from the fermentation step.

In this step the fermentation solution for which alcoholic fermentation has been completed is transferred to a sealed tank and stored. The storage conditions are not essentially different from those known in the art; and for example, the storage temperature is preferably from 0 to 2° C. and the fermentation time is preferably from 20 to 90 days. The fermentation-finished solution is stored to cause the remaining extract to undergo refermentation and maturation.

The fourth step of this invention is a filtration step of filtering the malt alcohol beverage intermediate product obtained from the storage step to produce the malt alcohol beverage.

The filtration conditions are not essentially different from those known in the art: for example, filtration aids such as diatomaceous earth, PVPP (polyvinylpolypyrrolidone), silica gel, and cellulose powder are used and the filtration is carried out at a temperature of 0±1° C. Thus the malt alcohol beverages (such as beer or low-malt beer) are produced. After the filtered malt alcohol beverages are subjected to sterile filtration or heating treatment, they are filled into tanks, barrels, bottles or cans and are shipped to the market.

The malt alcohol beverage of this invention is produced by having undergone the step of removing through adsorption at least a part of rough flavor components from malt, the malt alcohol beverage intermediate product, or the malt alcohol beverage (which will be referred to as “treated solution”) with the aid of an adsorbent at any of from the first step to the fourth step, plural steps or between the first step and the fourth step.

In the method of producing a malt alcohol beverage according to this invention, the step of removing rough flavor components through adsorption with the aid of an adsorbent may be either at any of from the first step to the fourth step or between the steps, but it should preferably be carried out before filtration in the fourth step. Alternatively, the adsorptive removal of the rough flavor components may be carried out between the steps by contacting the treated solution with the adsorbent in a container or in a transfer line.

The Adsorbents used in this invention and the substances to be adsorbed by the adsorbents will be described hereunder.

The adsorbents according to this invention may be any adsorbents having the function of reducing the stale flavor by removing the rough flavor components through adsorption, and include, for example, ion-exchange resins, synthetic adsorbents, and the like.

The ion-exchange resins may be largely classified into strongly acidic cation-exchange resins, weekly acidic cation-exchange resins, strongly basic anion-exchange resins, and weekly basic anion-exchange resins. The strongly/weekly acidic cation-exchange resins may be classified into the styrene type, the acrylic type and the methacrylic type; the strongly/weekly basic anion-exchange resins may be classified into the styrene type and the acrylic type. The strongly/weekly acidic cation-exchange resins, for example, include SK1B, SK104, SK110, SK112, SK116, PK208, PK212, PK216, PK220, PK228, WK10, WK11, WK100, WT01S, WK40, UBK530, UBK550, UBK535, UBK555 (all available from Mitsubishi Chemical Corporation), IR120BNa, IR124Na, IR118H, IRC50 and IRC76 (all available from Organo Corporation). The strongly/weekly basic anion-exchanqe resins, for example, include SA10A, SA11A, SA12A, NSA100, SA20A, SA21A, PA308, PA312, PA312, PA316, PA408, PA412, PA418, HPA25, HPA75, WA10, WA20, WA21J, WA30 (all available from Mitsubishi Chemical Corporation), IRA400C1, IRA402BLC1, IRA410C1, IRA96SB, IRA67, and IRAXE583 (all available from Organo Corporation). Among the aforementioned ion-exchange resins WA10, WA20, WA30, IRA67, IRA96SB, and IRAXE583 are preferably used, and WA10, WA20 and WA30 are more preferably used When the ion-exchange resin is to be used, it may be used after the exchange groups have been converted to any ionic type of the OH⁻, Cl^('), sulfuric acid and hydrogensulfite types by pretreatment. Specifically, after the ion-exchange resin is washed with distilled water, it is pretreated with NaCl aqueous solution or HCl aqueous solution, in which case the Cl⁻type can be obtained. When it is pretreated with NaOH aqueous solution, the OH⁻type can be obtained; when it is pretreated with H₂SO₄ aqueous solution, the sulfuric acid type can be obtained; and when it is pretreated with NaHSO₃ aqueous solution, the hydrogensulfite type can be obtained.

When the ion-exchange resin is used, the pH of the malt alcohol beverage can be adjusted depending on the ionic type. For example, when the pH of the malt alcohol beverage is to be raised, various ion-exchange resins of which the ionic type is OH⁻may be used. On the other hand, when the pH is to be lowered, the ionic type of Cl⁻or sulfuric acid may be used. Alternatively, ion-exchange resins of plural ionic types may be combined for use.

The aforementioned synthetic adsorbents may be largely classified into the aromatic type, the substituted aromatic type, and the acrylic type based on their chemical structures. Synthetic adsorbents of the aromatic type, for example, include HP20, HP21, SP825, SP850, SP70, SP700 (all available from Mitsubishi Chemical Corporation), XAD2 and XAD4 (all available from Organo Corporation). Synthetic adsorbents of the substituted aromatic type, for example, include SP207 (available from Mitsubishi Chemical Corporation). Synthetic adsorbents of the acrylic type include HP1MG, HP2MG (all available from Mitsubishi Chemical Corporation), XAD7 (available from Organo Corporation). Among these HP20, SP825, XAD2, XAD4, SP207, HP1MG and XAD7 are preferably used.

In the process of producing a malt alcohol beverage, the aforementioned adsorbent may be used alone or a plural number of adsorbents may be used in combination.

In the method of producing a malt alcohol beverage according to this invention, the rough flavor components that are removed through adsorption include causative substances for stale flavor, precursor substances thereof, or organic acids.

The causative substances for stale flavor, for example, include carbonyl compounds and Maillard compounds. These reaction intermediates and final reaction products are also included in the causative substances for stale flavor. Concrete examples of carbonyl compounds, for example, include propanal, hexanal, hexenal, pentanal, furfural, trans-2-nonenal and phenylacetaldehyde. Concrete examples of Maillard compounds, for example, include 5-hydroxymethylfurfural and Amadori substances, precursor thereof, which are the reaction products of sugars (such as glucose and fructose) and amino acids. The Amadori substances, for example, include glucose-glycine, glucose-alanine, glucose-leucine, glucose-isoleucine, fructose-proline, fructose-glutamic acid, fructose-serine, and fructose-threonine. Further included are heterocyclic compounds having a pyrazine ring, pyrrole ring, or imidazole ring such as pyrazine, 2-methylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, and trimethylpyrazine, for which the maillard reaction has progressed. Still further as causative substances that yield stale flavor other than the substances mentioned above there are mentioned the causative substances for stale flavor that are resulted from the decomposition of unsaturated fatty acids. Here, by selectively removing not only the causative substances for stale flavor but also precursors thereof (such as unsaturated fatty acids) through adsorption, it will be possible to suppress the formation of their decomposed products and to reduce the stale flavor.

The aforementioned organic acids are substances that produce sourness and rough flavors by being present in the malt alcohol beverage. Specifically there are mentioned pyroglutamic acid, acetic acid, lactic acid, succinic acid, malic acid, pyruvic acid, citric acid, fumaric acid and isocitric acid.

A majority of the causative substances for stale flavor including the unsaturated fatty acids mentioned above are highly hydrophobic substances. Such hydrophobic substances are removed through adsorption by. the adsorbents mentioned above, which allows the causative substances for stale flavor to be effectively eliminated.

In contrast, the substances that are essential to the flavor of a malt alcohol beverage and that should remain in the malt alcohol beverage without being adsorbed by the adsorbents of this invention include, for example, iso-α acid and reduced iso-α acid. Iso-α acid is a substance that produce bitterness in the malt alcohol beverage, and its degree of bitterness is expressed in terms of BU unit or the content of iso-α acid (mg/l): the former bitterness unit is quantified by measuring absorbance at 275 nm after addition of 6N hydrochloric acid solution to the malt alcohol beverage and extraction with isooctane; and the latter is measured by HPLC according to the method of BCOJ (Brewery Convention of Japan) or ASBC (American Society of Brewing Chemists). Because iso-α acid has high hydrophobicity, it tends to be adsorbed by the adsorbent. the amount of iso-α acid adsorbed to the adsorbent of this invention is determined and the resin with a small amount of adsorption is selected. Thus, it is possible to select the type of adsorbent suitable to the method of producing a malt alcohol beverage according to this invention. Specifically, after rough flavor components are removed through adsorption using an adsorbent, the decrease in BU for the malt alcohol beverage is preferably 0-50% and more preferably 5-30%. In order to have the lowered BU value returned and to have the lost hop flavor regained both of which are caused by adsorptive treatment with the adsorbent, iso-α acid, iso-hop extract, or its equivalent may be added during the production of the malt alcohol beverage, or alternatively iso-α acid, iso-hop extract, or its equivalent may be added prior to the adsorptive treatment in consideration of the BU value to be decreased and the lost hop flavor resulting from adsorption.

There will be next described the method for measuring the contents of various components, including the rough flavor components, that are present in the malt alcohol beverage in accordance with this invention. Measurement of various components, including the rough flavor components, that are present in the malt alcohol beverage is not only essential to the investigation of conditions under which the adsorbents of this invention are determined, but also is an essential means for the quality control of the malt alcohol beverage that has undergone removal of the rough flavor components by adsorption with the aid of the adsorbent.

For a device or method for measuring various components including the rough flavor components, HPLC or gas chromatography (GC) may, for example, be used. When the adsorbed amount of the substance described above is determined using HPLC, the malt alcohol beverage may be used as a sample and water/acetonitrile as a mobile phase to effect detection at 280 nm UV. When an ODS (silica gel bound with octadecyl groups) column is used as the filler, the peaks appeared resulting from elution often contain highly hydrophilic substances in the first half and highly hydrophobic substances in the second half. When the contents of the causative substances for stale flavor are to be measured, hydrophobic peaks should be caught attention and may be measured. When gas chromatography is used to measure the adsorbed amounts described above, the malt alcohol beverage may be used as a sample, and after extraction with organic solvents such as ether-pentane or solid-phase extraction, measurement can be made using conventional techniques. In any measurement described above, these substances in the sample may be directly or chemically modified as necessary, after which measurement may be made.

The methods described above are used to determine the presence or absence of or the contents of the substances that influence the flavor of the malt alcohol beverage. This makes it possible to appropriately select an adsorbent capable of selectively removing the rough flavor components as well as to find the adequate amount of the adsorbent to be added to the malt alcohol beverage. Accordingly, by using the adsorbent selected by the aforementioned method, it will be possible to remove only the rough flavor components and to produce the malt alcoholic beverage that has excellent flavor and that can maintain the flavor immediately after production over a prolonged period of time.

EXAMPLES

This invention will be described in further detail by way of examples hereunder; however, the invention should not be limited to these examples.

Examples 1-70 and Comparative Examples 1-14

Three hundred milliliters of malt alcohol beverages (two types: low-malt beer and beer), from which CO₂ had been removed by ultrasonication, was transferred to 500 ml-beakers for preparation. To the respective beverages was added ion-exchange resins or synthetic adsorbents that had been filtered through an extensively washed glass filter at amounts of addition indicated below and the pH of the malt alcohol beverage was measured with time at stirring. With respect to HPLC peak, the content of iso-α acid, the content of organic acid, and the content of total polyphenol, measurement was made with the malt alcohol beverages that had been stirred for 3 hours. Here, iso-a acid was analyzed using HPLC and total polyphenol was analyzed according to the BCOJ method (ammonium iron (III) citrate, carbozinmethylcellulose, ethylenediaminetetraacetic acid and ammonia water were added to develop color, after which the measurement was done at 600 nm). All the manipulations above were conducted at room temperature.

(Ion-Exchange Resins)

The ion-exchange resins used are shown in Table 1. TABLE 1 WA10 WA20 WA30 IR67 IRA96SB XE583 feature acrylic styrene styrene acrylic styrene styrene type type type type type type gel type porous hyperporous gel type type type white light light white light light transparent yellow yellow tansparent yellow yellow spherical opaque opaque spherical opaque opaque spherical spherical spherical spherical water 63-69 39-45 43-55 56-62 56-62 48-54 content exchange 1.2 or more 2.5 or 1.5 or more 1.6 1.2 1.5 capacity more (meq/ml)

The ion-exchange resins used and the amounts of their addition are shown below. amount of examples resin name addition (g/100 ml) 1, 13, 25, 37 WA10 0.2 2, 14, 26, 38 WA10 1 3, 15, 27, 39 WA20 0.2 4, 16, 28, 40 WA20 1 5, 17, 29, 41 WA30 0.2 6, 18, 30, 42 WA30 1 7, 19, 31, 43 IRA67 0.2 8, 20, 32, 44 IRA67 1 9, 21, 33, 45 IRA96SB 0.2 10, 22, 34, 46 IRA96SB 1 11, 23, 35, 47 IRAXE583 0.2 12, 24, 36, 48 IRAXE583 1

Here, the resins were washed with distilled water, then with. 1N-HC1, distilled water, and 1N-NaOH in this order, and they were washed with distilled water until they turned neutral, by which they were made a Cl⁻type or a OH⁻type. In addition, WA10, WA20, and WA30 were available from Mitsubishi Chemical Corporation and IRA67, IRA96SB and IRAXE583 were available from Organo Corporation.

The ion types of the ion-exchange resins and the samples used in Example 1 to 48 are as follows:

-   Examples 1-12: Ion-exchange resin of which the ion type is OH⁻and     low-malt beer -   Examples 13-24: Ion-exchange resin of which the ion type is Cl⁻and     low-malt beer -   Examples 25-36: Ion-exchange resin of which the ion type is OH⁻and     beer -   Examples 37-48: Ion-exchange resin of which the ion type is Cl⁻and     beer

Variations in the pH of the malt alcohol beverages after treatment with ion-exchange resins are shown in FIGS. 1-4. The results from Examples 1-6 are shown in FIG. 1A, the results from Examples 7-12 in FIG. 1B, the results from Examples 13-18 in FIG. 2A, the results from Examples 19-24 in FIG. 2B, the results from Examples 25-30 in FIG. 3A, the results from Examples 31-36 in FIG. 3B, the results from Examples 37-42 in FIG. 4A, and the results from Examples 43-48 in FIG. 4B. In the figures IAXE583 is indicated as “IRAXE,” and the amount of addition for an ion-exchange resin (g/100ml) is shown in the bracket.

Consequently, when the ion type of an ion-exchange resin was OH⁻, the pH of the treated malt alcohol beverage increased; whereas the pH decreased when the ion type was Cl⁻.

FIGS. 5-12 graphically show the sum of peak areas when the components of a malt alcohol beverage were detected by HPLC after treatment with ion-exchange resins. With respect to the peaks appeared resulting from elution, it was likely that there were obtained those of hydrophilic components in the first half of elution and there were obtained those of hydrophobic components in the second half of elution. Graphic representation was made such that the first half portions of elution are hydrophilic peaks and the is second half portions of elution are hydrophobic peaks.

The hydrophilic peaks from Examples 1-6 and the control (Comparative Example 1) are shown in FIG. 5A; the hydrophobic peaks from Examples 1-6 and the control (Comparative Example 1) are shown in FIG. 5B. The hydrophilic peaks from Examples 7-12 and the control (Comparative Example 2) are shown in FIG. 6A; the hydrophobic peaks from Examples 7-12 and the control (Comparative Example 2) are shown in FIG. 6B. The hydrophilic peaks from Examples 13-18 and the control (Comparative Example 5) are shown in FIG. 7A; the hydrophobic peaks from Examples 13-18 and the control (Comparative Example 5) are shown in FIG. 7B. The hydrophilic peaks from Examples 19-24 and the control (Comparative Example 6) are shown in FIG. 8A; the hydrophobic peaks from Examples 19-24 and the control (Comparative Example 6) are shown in FIG. 8B. The hydrophilic peaks from Examples 25-30 and the control (Comparative Example 5) are shown in FIG. 9A; the hydrophobic peaks from Examples 25-30 and the control (Comparative Example 5) are shown in FIG. 9B. The hydrophilic peaks from Examples 31-36 and the control (Comparative Example 6) are shown in FIG. 10A; the hydrophobic peaks from Examples 31-36 and the control (Comparative Example 6) are shown in FIG. 10B. The hydrophilic peaks from Examples 37-42 and the control (Comparative Example 7) are shown in FIG. 11A; the hydrophobic peaks from Examples 37-42 and the control (Comparative Example 7) are shown in FIG. 11B. The hydrophilic peaks from Examples 43-48 and the control (Comparative Example 8) are shown in FIG. 12A; the hydrophobic peaks from Examples 43-48 and the control (Comparative Example 8) are shown in FIG. 12B. In the figures peak area is indicated as “mAu*S” and the amount of addition for an ion-exchange resin (g/100ml) is shown in the bracket.

Consequently, it has been confirmed that hydrophobic components are adsorbed on the ion-exchange resin. It has also been confirmed that when WA30, IRA96SB or IRAXE583 is used, there is a greater amount of adsorbed components and that the more the amount of addition for an adsorbent is, the higher the effect of adsorption becomes.

Furthermore, the contents of organic acids in malt alcohol beverages after treatment with ion-exchange resins are shown in FIGS. 16-17. Examples 1-6, 13-18 and the control (Comparative Examples 1 and 3) are shown in FIG. 16A; Examples 7-12, 19-24 and the control (Comparative Examples 2 and 4) are shown in FIG. 16B. Examples 25-30, 37-42 and the control (Comparative Examples 5 and 7) are shown in FIG. 17A; Examples 31-36, 43-48 and the control (Comparative Examples 6 and 8) are shown in FIG. 17B. In FIGS. 16-17, the ion-exchange resins of which the ion type is Cl⁻are indicated as “the name of resin-Cl,” while the ion-exchange resins of which the ion type is OH⁻are indicated only in terms of their names. In the figures, the amount of addition for an ion-exchange resin (g/100ml) is shown in the bracket.

Various organic acids were adsorbed on the resin the ion type of which was either OH⁻or Cl⁻; among those citric acid tended to be adsorbed to the greatest extent, and either of acetic acid and pyroglutamic acid was hardly adsorbed.

The contents of polyphenols in malt alcohol beverages after treatment with ion-exchange resins are shown in FIGS. 18-19. Examples 1-6, 13-18 and the control (Comparative Examples 1 and 3) are shown in FIG. 18A; Examples 7-12, 19-24 and the control (Comparative Examples 2 and 4) are shown in FIG. 18B. Examples 25-30, 37-42 and the control (Comparative Examples 7 and 9) are shown in FIG. 19A; Examples 31-36, 43-48 and the control (Comparative Examples 8 and 10) are shown in FIG. 19B. In each figure, the amount of addition for an ion-exchange resin (g/100ml) is shown in the bracket.

Consequently, it has been confirmed that when WA30, IRA96SB or IRAXE583 is used, polyphenols tend to be adsorbed.

(Synthetic Adsorbents)

The synthetic adsorbents used are shown in Tables 2 and 3. TABLE 2 HP1MG SP207 SB825 HP20 material methacrlylic aromatic type styrene- styrene- type divinyl- divinyl- benzene benzene type type water 63.0 50.4 56.1 56.5 content specific 333 627 977 511 surface area (m²/g) feature High polarity strong hydrophobicity

TABLE 3 XAD2 XAD4 XAD7 material styrene type styrene type acrylic type surface area 300 725 450 (m²/g) Water content 47 48 69 mean pore 100 48 85 diameter specific 333 627 977 surface area (m²/g) feature non-polar non-polar

The synthetic adsorbents used and their amounts of addition are shown below. amount of addition time of example adsorbent (g/100 ml) addition (h) Examples XAD2 1 1 49, 59 Examples XAD4 1 1 50, 60 Examples XAD4 0.1 3 51, 61 Examples XAD7 1 1 52, 62 Examples XAD7 0.1 3 53, 63 Examples HP1MG 1 1 54, 64 Examples SP207 1 1 55, 65 Examples HP20 1 1 56, 66 Examples HP20 0.1 3 57, 67 Examples SP825 1 1 58, 68

Examples 49-58 show the cases where the low-malt beer was subjected to measurement, and Examples 59-68 show the cases where beer was subjected to measurement.

Graphic representation for the sum of peak areas as detected by HPLC is as follows. The hydrophilic peaks from Examples 49-58 and the control (Comparative Example 11) are shown in FIG. 13A; the hydrophobic peaks from Examples 49-58 and the control (Comparative Example 11) are shown in FIG. 13B. The hydrophilic peaks from Examples 59-68 and the control (Comparative Example 12) are shown in FIG. 14A; the hydrophobic peaks from Examples 59-68 and the control (Comparative Example 12) are shown in FIG. 14B. In FIG. 14, “(1h)” indicates that the time of addition for a synthetic adsorbent is one hour, and “(0.1)” indicates that the amount of addition for a synthetic adsorbent is 0.1 g/ml.

Consequently, it has been confirmed that there is a great deal of adsorption of the components in the malt alcohol beverage by SP207, SP825, XAD2, or XAD7.

FIG. 15 shows variations in the concentrations of iso-α acid in the malt alcohol beverages when a variety of synthetic adsbrbents were added. Here, measurement was also made where DEAE was used in place of the synthetic adsorbent (Comparative Example 13).

Consequently, it has been confirmed that there is little adsorption of iso-α acid in the malt alcohol beverage when XAD4 or HP1MG is used.

The contents of polyphenols in the low-inalt beers or beers to which various synthetic adsorbents were added are shown in FIG. 18C with respect to Examples 49-58 and the control (Comparative Example 11) and FIG. 19C with respect to Examples 59-68 and the control (Comparative Example 12). The contents of polyphenols were also measured where PVPP(F) (Example 69), PVPP(RS) (Example 70), DEAE (Comparative Example 13) and SiO₂ (Comparative Example 14). In the figure “( )” indicates the amount of addition for a synthetic adsorbent (g/ml).

Consequently, it has been confirmed that the power of adsorption of polyphenols by a synthetic adsorbent exhibits similar trends in the low-malt beer and the beer and that there is a great deal of adsorption of polyphenols in the malt alcohol beverage when HP1MG, HP20, SP825, SP207, XAD2, or XAD7 is used. In the cases of SiO₂ and DEAE, the adsorption of polyphenols was hardly observed.

Examples 71-88 and Comparative Examples 15-20

After the synthetic adsorbents were heated in sterilized water at 60° C. for 1 hour, they were filtered through a glass filter. These adsorbents were respectively added to the malt alcohol beverages (633 ml), and the space was filled with foam by knocking to remove as much oxygen as possible from the space, after which tapping was done. After they were shaken at room temperature for 2 hours, they were stored at 37° C. for 1 week and analytical and sensory evaluations were carried out. The sensory evaluation was carried out according to the profile method: the trained panel evaluated stale odor, paper odor, oxidation odor and the overall degree of aging in a sensory manner, and the data was provided for statistical analysis.

First, among the synthetic adsorbents (HP1MG, XAD4 and XAD7), HP1MG was added to the malt alcohol beverage to provide the final concentrations of 0.1 g/100 ml, 0.2 g/100 ml, and 0.4 g/100 ml; XAD4 was added to the malt alcohol beverage to provide the final concentrations of 0.2 g/100 ml and 0.4 g/100 ml; and XAD7 was added to the malt alcohol beverage to provide the final concentrations of 0.1 g/100 ml, 0.2 g/100 ml, and 0.4 g/100 ml. After storing at 37° C. room temperature for 1 week, the sensory evaluation was carried out. Results are shown in Tables 4-6 (Examples 71-78 and Comparative Examples 15-17). In the tables the inside the bracket indicates the concentration of adsorbent (g/100 ml): the results are expressed in terms of a value of from 0 to 4 and the greater value represents a higher degree of stale flavor. The values were validated by examination using the Friedman calibration; in the tables “*” indicates p<0.05 and “**” indicates p<0.01. TABLE 4 Example Example Example Comparative 71 72 73 Example 15 HP1MG HP1MG HP1MG control (0.1) (0.2) (0.4) stale 2.4 2.5 1.6* 1.9 odor paper 2.1 2.1 1.1* 1.4 odor oxidation 1.4 1.4 1.2 1.1 odor overall 2.4 2.4 1.5 2.0 degree of aging

TABLE 5 Comparative Example 16 Example 74 Example 75 control XAD4 (0.2) XAD4 (0.4) stale 2.5 2.1 2.2 odor paper 2.1 1.6 1.5 odor oxidation 1.5 1.4 1.4 odor overall 2.6 2.1 2.1 degree of aging

TABLE 6 Example Example Example Comparative 76 77 78 Example 17 XAD7 XAD7 XAD7 control (0.1) (0.2) (0.4) stale 2.4 1.6* 1.9 1.9 odor paper 2.4 1.3** 1.6* 1.4 odor oxidation 0.9 0.6 0.9 0.8 odor overall 2.4 1.6* 1.7* 1.7* degree of aging

Consequently, it has become apparent that when 0.2 g/100 ml of HP1MG is used, the paper odor and the stale odor are significantly lower than the control. It has also been confirmed that when XAD7 is used, the stale odor, the paper odor, and the overall degree of aging are all significantly lower than the control.

Next, one week after the addition of various synthetic adsorbents, the sensory evaluation was carried out with the panel number of 8 (HP1MG, SP825, and SP207) or with the panel number of 10 (XAD2, XAD4, and XAD7). Results are shown in Tables 7 and 8 (Examples 79-84 and Comparative Examples 18-19). TABLE 7 Comparative Example Example Example Example 18 79 80 81 Control HP1MG SP825 SP207 stale 2.4 1.9 2.3 2.3 odor paper 2.6 1.3** 1.4* 1.1* odor oxidation 1.7 1.4 1.9 1.9 odor overall 2.9 1.9** 2.3* 2.1** degree of aging

TABLE 8 Comparative Example Example Example Example 19 82 83 84 control XAD2 XAD4 XAD7 stale 2.9 2.2** 2.5 2.0** odor paper 2.7 1.5** 1.8** 1.5** odor oxidation 2.1 1.4** 1.8 1.5** odor overall 2.9 2.1** 2.5 1.9** degree of aging

Consequently, it has been confirmed that when any of HP1MG, SP825, and SP207 is used, the paper odor and the overall degree of aging are significantly lower than the control. It has also been confirmed that when either XAD2 or XAD7 is used, the stale odor, the paper odor and the overall degree of aging are all significantly lowered as compared to the control and that when XAD4 is used, the paper odor is also lowered as compared to the control.

Furthermore, after the synthetic adsorbents were added following the aforementioned method, the space was filled with foam by knocking and tapping was done. Subsequently, the adsorbents were removed from the malt alcohol beverages by shaking for 2 hours and they were then stored at 37° C. for 1 week to conduct the sensory evaluation. Results are shown in Table 9 (Examples 85-88 and Comparative Example 20). TABLE 9 Example Example Example Example Comparative 85 86 87 88 Example 20 HP1MG HP1MG XAD4 XAD7 control (0.2) (0.4) (0.2) (0.2) stale 2.5 1.6 1.8 1.9 1.9 odor paper 2.3 1.1** 1.2** 1.6 1.2** odor oxidation 1.6 1.1 1.2 1.2 1.2 odor overall 2.5 1.4** 1.7* 1.8 1.7* degree of aging

Consequently, it has been confirmed that when HP1MG or XAD7 is used, the paper odor and the overall degree of aging are significantly lower than the control.

The results of the sensory evaluations as described above indicate that the stale flavor, especially stale odor and paper odor, has been reduced by addition of the synthetic adsorbents. Particularly, the paper odor showed noted reduction and thus the effects of adsorbent were recognized.

Examples 89-136 and Comparative Examples 21-31

To the low-malt beer or beer (each 20 liter) there were added a filtration aid (diatomaceous earth) which is used in ordinary production processes and a 2 g/l equivalent (as wet weight) of a synthetic adsorbent (HP1MG, XAD-4, or XAD-7), after which filtration was conducted. As for HP1MG, addition at a level of 4 g/l equivalent was also conducted. Thus, a preparation to which 4 g/l of HP1MG (as wet weight) had been added was made (indicated as “HP1MGX2” in the table). The filtered low-malt beer solutions were stored at 37° C. for 1 week or stored at 30° C. for 1 month, and then they were analyzed for bitterness unit (BU), the content of total polyphenol, calorimetric analysis value, HPLC peak, the content of trans-2-nonenal, and sensory evaluation.

The results of the sensory evaluation that was conducted on the low-malt beers before storage are shown in Table 10 (Examples 89-92 and Comparative 21), and the results of the sensory evaluation that was conducted on the beers before storage are shown in table 11 (Examples 93-96 and Comparative 22). TABLE 10 Exam- Exam- Comparative Example Example ple ple Example 21 89 90 91 92 control HP1MGX1 HP1MGX2 XAD4 XAD7 flavor 100 102 97 102 98 point taste 100 94 94 94 97 point body 100 100 100 100 99 point after 100 100 104 99 103 taste point bitterness 100 103 103 101 101 point overall 100 100 99 99 100

TABLE 11 Comparative Example Example Example Example Example 22 93 94 95 96 control HP1MG HP20 XAD4 XAD7 flavor 100 100 100 94 102 point taste 100 98 100 106 96 point body 100 108 100 104 106 point after 100 98 102 102 98 taste point bitterness 100 100 102 98 102 point overall 100 100 101 100 101

The results of the sensory evaluation conducted on the low-malt beers after storage at 37° C. for 1 week are shown in Table 12 (Examples 97-100 and Comparative 23); the results after storage at 30° C. for 1 month are shown in Table 13 (Examples 101-104 and Comparative 24). The results of the sensory evaluation conducted on the beers after storage at 37° C. for 1 week are shown in Table 14 (Examples 105-108 and Comparative 25); the results after storage at 30° C. for 1 month are shown in Table 15 (Examples 109-112 and Comparative 26). The values were validated by examination using the Friedman calibration: in the tables “*” indicates p<0.05 and “**” indicates p<0.01. TABLE 12 Exam- Exam- Comparative Example Example ple ple Example 23 97 98 99 100 control HP1MGX1 HP1MGX2 XAD4 XAD7 stale 2.6 2.2 1.9** 2.0* 2.2 odor paper 2.5 1.5* 1.5** 2.0 1.7 odor oxidation 1.5 1.2 1.0 1.1 1.1 odor overall 2.8 2.2 1.8** 2.1* 2.2 degree of aging

TABLE 13 Exam- Exam- Comparative Example Example ple ple Example 24 101 102 103 104 control HP1MGX1 HP1MGX2 XAD4 XAD7 stale 2.3 1.8* 1.9 1.9* 2.3 odor paper 2.2 1.4 1.4 1.7 1.6 odor oxidation 1.6 1.4 1.6 1.4 1.6 odor overall 2.3 1.8 2.0 1.9 2.4 degree of aging

TABLE 14 Comparative Example Example Example Example Example 25 105 106 107 108 control HP1MG HP20 XAD4 XAD7 stale 1.7 1.4 1.2* 1.4 1.6 odor paper 1.8 1.2 1.2 1.5 1.3 odor oxidation 1.1 0.9 0.9 1.2 1.0 odor overall 1.9 1.4 1.2* 1.7 1.6 degree of aging

TABLE 15 Comparative Example Example Example Example Example 26 109 110 111 112 control HP1MG HP20 XAD4 XAD7 stale 2.3 1.8 1.9 2.2 1.9 odor paper 2.1 1.6* 1.4 2.1 1.6* odor oxidation 1.3 1.2 1.3 1.6 1.4 odor overall 2.2 1.8 1.9 2.3 1.8 degree of aging

Consequently, while there were some noted differences in flavor, taste or the like either between the control and the low-malt beer or between the control and the beer, they were not significant; and flavors inferior to that in the control were not noted. However, after storage at 37° C. for 1 week, in both low-malt beer and beer there were noted significant reductions in the stale flavor, especially stale odor and paper odor, as compared to the control even when any of the adsorbent was added. Furthermore, after storage at 30° C. for 1 month, reductions in the stale odor and the paper odor were significantly noted in the low-malt beers. On the other hand, reductions in the stale odor and the paper odor were noted in the beers, although the adsorption effects of the stale flavor by HP1MG and HP20 were remarkable.

The results on the bitterness unit (expressed as BU), the content of total polyphenol, and calorimetric analysis value for the low-malt beers are shown in Table 16 (Examples 113-116 and Comparative Example 26); the results on the aforementioned items for the beers are shown in Table 17 (Examples 117-120 and Comparative 27). TABLE 16 Exam- Exam- Comparative Example Example ple ple Example 26 113 114 115 116 control HP1MGX1 HP1MGX2 XAD4 XAD7 BU 24.5 20.1 16.4 23.3 16.4 total 122 96 96 116 104 poly- phenol (mg/L) chroma- 9.9 9.2 8.8 9.6 8.7 ticity (EBC°)

TABLE 17 Comparative Example Example Example Example Example 27 117 118 119 120 control HP1MGX1 HP20 XAD4 XAD7 BU 21.9 21.0 15.4 18.0 14.8 total 182 173 169 149 162 poly- phenol (mg/L) chroma- 8.2 7.4 7.7 8.1 7.3 ticity (EBC°)

Consequently, portions of iso-α acid, total polyphenol and the chromaticity were adsorbed by the adsorbents in either of the low-malt beer and the beer. The amount of adsorption by XAD4 tended to be smaller than those by the other adsorbents.

FIGS. 20-21 show the sum of peak areas as detected by HPLC. It has been confirmed that in either of the low-malt beer and the beer, HPLC peaks with high hydrophobicity are susceptible to adsorption by the adsorbents. While the amounts of adsorption by XAD4 tended to be smaller than those by the other adsorbents in the low-malt beer, there was no such tendency observed in the beer.

The contents of trans-2-nonenal contained in the low-malt beers after storage are shown in Table 18 (Examples 121-124 and Comparative Example 28); the contents of trans-2-nonenal increased during storage are shown in Table 19 (Examples 125-128 and Comparative Example 29). The contents of trans-2-nonenal contained in the beers after storage are shown in Table 20 (Examples 129-132 and Comparative Example 30); the contents of trans-2-nonenal increased during storage are shown in Table 21 (Examples 133-136 and Comparative Example 31). In the tables, “30° Clm” indicates the cases where storage at 30° C. for 1 month was effected and “37° Clw” indicates the cases where storage at 37° C. for 1 week was effected. TABLE 18 Exam- Exam- Comparative Example Example ple ple Example 28 121 122 123 124 control HP1MGX1 HP1MGX2 XAD4 XAD7  0° C. 0.10 0.07 0.07 0.09 0.08 37° C.1 w 0.29 0.24 0.14 0.24 0.18 30° C.1 m 0.33 0.2 0.16 0.33 0.18

TABLE 19 Exam- Exam- Comparative Example Example ple ple Example 29 125 126 127 128 control HP1MGX1 HP1MGX2 XAD4 XAD7 37° C.1 w 0.19 0.17 0.07 0.15 0.10 30° C.1 m 0.23 0.13 0.09 0.24 0.10

TABLE 20 Comparative Example Example Example Example Example 30 129 130 131 132 control HP1MG HP20 XAD4 XAD7 0° C. 0.08 0.11 0.07 0.12 0.08 37° C.1 w 0.17 0.14 0.1 0.15 0.1 30° C.1 m 0.18 0.14 0.12 0.16 0.1

TABLE 21 Comparative Example Example Example Example Example 31 133 134 135 136 control HP1MG HP20 XAD4 XAD7 37° C.1 w 0.09 0.03 0.03 0.03 0.02 30° C.1 m 0.1 0.03 0.05 0.04 0.02

Consequently, trans-2-nonenal was adsorbed by the adsorbent and the content of trans-2-nonenal decreased in either of the low-malt beer and the beer even after storage, except for the case where the low-malt beer was stored with the use of XAD4 at 30° C. for 1 month. It was likely that storage in the presence of the adsorbent suppresses an increase in trans-2-nonenal. It was thus thought that elimination of precursors of trans-2-nonenal by the adsorbent was also occurring.

Examples 137-171 and Comparative Examples 32-40

After HP1MG, a synthetic adsorbent, was heated in sterilized water at 60° C. for 1 hour, it was filtered through a glass filter. This was added to the malt alcohol beverage (or beer), 633 ml, at concentrations of 0.2 g/100 ml, 1.0 g/100 ml, and 5.0 g/100 ml, respectively; and the space was filled with foam by knocking to remove as much oxygen as possible from the space, after which tapping was done. After they were shaken at room temperature for 2 hours, they were stored at 37° C. for 1 week and the sensory evaluations were carried out. The sensory evaluation was carried out according to the profile method: the trained panel evaluated color, flavor, taste, after taste, body and bitterness in a sensory manner and the data was provided for statistical analysis. Simultaneously, measurement of bitterness unit (BU) was also carried out. Results are shown in Table 22 (Examples 137-139 and Comparative Example 32). TABLE 22 Comparative Example Example Example Example 32 137 138 139 control 0.2 g/100 ml 1.0 g/100 ml 5.0 g/100 ml color 100 100 95 79 flavor 100 102 90 63 taste 100 100 75 65 after 100 103 97 72 taste body 100 90 69 62 bitterness 100 98 77 67 BU 0 24 48 86 adsorption (%)

To the malt alcohol beverage (low-malt beer or beer) there was added the synthetic adsorbent, HP1MG, XAD4 or XAD7, at 2 g/l as wet weight. After storing at 30° C. for 1 month or at 37° C. for 1 week, the contents of 2-Me-propanal, 2-Me-butanal, 3-Me-butanal, and phenylacetaldehyde contained the malt alcohol beverage were determined. As for HP1MG, a preparation to which 4 g/l of HP1MG (as wet weight) had been added was made (indicated as “HP1MGX2” in the table).

The contents of 2-Me-propanal contained in the low-malt beers after storage are shown in Table 23 (Example 140-143 and Comparative Example 33), the contents of 2-Me-butanal in Table 24 (Example 144-147 and Comparative Example 34), the contents of 3-Me-butanal in Table 25 (Example 148-151 and Comparative Example 35), and the contents of phenylacetaldehyde in Table 26 (Example 152-155 and Comparative Example 36). The contents of 2-Me-propanal contained in the beers after storage are shown in Table 27 (Example 156-159 Comparative Example 37), the contents of 2-Me-butanal in Table 28 (Example 160-163 and Comparative Example 38), the contents of 3-Me-butanal in Table 29 (Example 164-167 and Comparative Example 39), and the contents of phenylacetaldehyde in Table 30 (Example 168-171 and Comparative Example 40). In the tables, “30° Clm” indicates the cases where storage was effected at 30° C. for 1 month and “37° Clw” indicates the cases where storage was effected at 37° C. for 1 week. The numerals in the tables are expressed as relative values when the control was taken as 100. TABLE 23 Exam- Exam- Comparative Example Example ple ple Example 33 140 141 142 143 control HP1MGX1 HP1MGX2 XAD4 XAD7  0° C. 100 76 63 80 72 37° C.1 w 100 89 87 94 83 30° C.1 m 100 88 84 89 81

TABLE 24 Exam- Exam- Comparative Example Example ple ple Example 34 144 145 146 147 control HP1MGX1 HP1MGX2 XAD4 XAD7  0° C. 100 68 58 84 68 37° C.1 w 100 73 60 83 67 30° C.1 m 100 84 71 85 63

TABLE 25 Exam- Comparative Example Example Example ple Example 35 148 149 150 151 control HP1MG HP1MGX2 XAD4 XAD7  0° C. 100 71 67 76 73 37° C.1 w 100 83 78 86 82 30° C.1 m 100 88 79 83 76

TABLE 26 Exam- Comparative Example Example Example ple Example 36 152 153 154 155 control HP1MG HP1MGX2 XAD4 XAD7  0° C. 100 115 84 107 108 37° C.1 w 100 98 106 86 96 30° C.1 m 100 101 101 89 89

TABLE 27 Exam- Exam- Comparative Example Example ple ple Example 37 156 157 158 159 control HP1MGX1 MP1MGX2 XAD4 XAD7  0° C. 100 78 58 75 64 37° C.1 w 100 98 93 103 94 30° C.1 m 100 92 82 88 82

TABLE 28 Exam- Exam- Comparative Example Example ple ple Example 38 160 161 162 163 control HP1MGX1 HP1MGX2 XAD4 XAD7  0° C. 100 89 82 91 85 37° C.1 w 100 90 85 97 85 30° C.1 m 100 92 88 90 88

TABLE 29 Com- parative Example Example Example Example Example 39 164 165 166 167 control HP1MG HP1MGX2 XAD4 XAD7  0° C. 100 80 73 77 72 37° C.1 w 100 98 72 78 72 30° C.1 m 100 91 86 85 87

TABLE 30 Com- parative Example Example Example Example Example 40 168 169 170 171 control HP1MG HP1MGX2 XAD4 XAD7  0° C. 100 93 73 84 74 37° C.1 w 100 88 78 88 81 30° C.1 m 100 84 75 84 81

Consequently, 2-Me-propanal, 2-Me-butanal and 3-Me-butanal were all adsorbed by any of the synthetic adsorbents, and their contents in the malt alcohol beverages decreased. However, no clear adsorption for penylacetaldehyde was noted when HPlMG was used in the low-malt beer, but the tendency of adsorption was observed with the use of XAD4 and XAD7. On the other hand, phenylacetaldehyde showed sufficient adsorption in the beer and its content decreased after adsorption.

Industrial Applicability

As described above, the method of producing a malt alcohol beverage according to this invention allows for providing a method of producing a malt alcohol beverage such that by removing through adsorption tough flavor components with the aid of an adsorbent during the production process of the malt alcohol beverage, the aging of flavor after production can be suppressed and the flavor immediately after production can be maintained. 

1-6. (canceled)
 7. A method of producing a malt alcohol beverage, comprising: removing through adsorption at least a part of rough flavor components from malt, a malt alcohol beverage intermediate product, or the malt alcohol beverage with the aid of a synthetic adsorbent.
 8. The method of producing a malt alcohol beverage according to claim 7, wherein the rough flavor component is a causative substance for stale flavor or a precursor thereof.
 9. The method of producing a malt alcohol beverage according to claims 7 or 8, wherein the rough flavor component is a carbonyl compound or a Maillard compound.
 10. The method of producing a malt alcohol beverage according to claims 7 or 8, wherein the rough flavor component is an organic acid.
 11. The method according to claim 7, further comprising: mixing a raw material containing malt with water, thereby obtaining a mixture; saccharifying the malt by warming the mixture, thereby obtaining saccharified malt; collecting wort from the saccharified malt; fermenting the wort by addition of yeast thereto, thereby obtaining the malt alcohol beverage intermediate product; storing the malt alcohol beverage intermediate product; and filtering the malt alcohol beverage intermediate product to produce the malt alcohol beverage.
 12. The method according to claim 11, wherein said rough flavor components are removed before the filtration of the malt alcohol beverage intermediate product.
 13. The method according to claim 7, wherein said adsorbent reduces a stale flavor of said malt alcohol beverage.
 14. The method according to claim 7, wherein the adsorbent is selected from the group consisting of SA10A, SA11A, SA12A, NSA100, SA20A, SA21A, PA308, PA312, PA312, PA316, PA408, PA412, PA418, HPA25, HPA75, WA10, WA20, WA21J, WA30, IRA400C1, IRA402BLC1, IRA410C1, IRA96SB, IRA67, and IRAXE583.
 15. The method according to claim 7, wherein said synthetic adsorbent is selected from the group consisting of an aromatic group containing adsorbent, a substituted aromatic group containing adsorbent, and an acrylic group containing adsorbent.
 16. The method according to claim 7, wherein said synthetic adsorbent is selected from the group consisting of HP20, HP21, SP825, SP850, SP70, SP700, XAD2, XAD4, SP207, HP1MG, HP2MG, and XAD7.
 17. The method according to claim 7, wherein the rough flavor component is propanal, hexanal, hexenal, pentanal, furfural, trans-2-nonenal, phenylacetaldehyde or a mixture thereof.
 18. The method according to claim 7, wherein the rough flavor component is 5-hydroxymethylfurfural, an Amadori substance, a precursor of an Amadori substance or a mixture thereof.
 19. The method according to claim 7, wherein the rough flavor component is selected from the group consisting of glucose-glycine, glucose-alanine, glucose-leucine, glucose-isoleucine, fructose-proline, fructose-glutamic acid, fructose-serine, fructose-threonine and mixtures thereof.
 20. The method according to claim 7, wherein the rough flavor component is a heterocyclic compound having a pyrazine ring, pyrrole ring, or imidazole ring.
 21. The method according to claim 7, wherein the rough flavor component is a product of the decomposition of an unsaturated fatty acid.
 22. The method according to claim 7, wherein an unsaturated fatty acid is removed.
 23. The method according to claim 22, wherein said unsaturated fatty acid is selected from the group consisting of pyroglutamic acid, acetic acid, lactic acid, succinic acid, malic acid, pyruvic acid, citric acid, fumaric acid, isocitric acid and mixtures thereof.
 24. The method according to claim 7, wherein a decrease in a degree of bitterness of the malt alcohol beverage after the adsorption is 0-50%. 